The present invention pertains to the field of electronic device connectors. More particularly, the present invention relates to reducing electromagnetic interference (EMI) leakage through a connector housing that is required to be electrically isolated from a chassis of a device to which the connector housing is coupled.
Connectors are used to couple together a wide variety of electronic devices including computers, peripheral devices, audio/video components, telephones, network terminals, etc. For instance, a personal computer may have several different connectors, both male and female, for hooking up components such as a monitor, a key board, and a mouse, and may include additional connectors for networking such as an Ethernet card connector.
For various reasons, connector housings are often xe2x80x9cisolatedxe2x80x9d from the ground (usually the chassis) of the device to which a connector housing is coupled. For instance, in the event of a xe2x80x9cground surge,xe2x80x9d such as a lightening strike on a telephone line leading to a computer, every component in the computer coupled to the chassis may experience a large and potentially damaging current. By isolating the connector housing from the chassis, a ground surge is less likely to be propagated to another device or into a network to which the connector leads.
FIGS. 1A and 1B illustrate one example of an isolated connector housing 120 in an electronic device 100. Chassis 110 contains a printed circuit board (PCB) 140. PCB 140 includes an integrated circuit (IC) 150, which is coupled to connector housing 120 through a bus 155. A signal path 150 couples bus 155 on PCB 140 through connector housing 120 to any of a number of peripheral devices, networks, etc. (not shown).
Connector housing 120 is indirectly coupled to chassis 110 in that connector housing 120 is mount to PCB 140 using mounting screws 160 and PCB 140 is mounted within chassis 110. Furthermore, connector aperture 130 in chassis 110 is larger than the dimensions of connector housing 120 so that connector housing 120 does not make direct contact with chassis 110. In which case, connector housing 120 is isolated from chassis 110.
Although isolating a connector from ground has certain advantages, it also has some disadvantages. For instance, if electronic device 100 generates electromagnetic interference (EMI), which virtually all electronic devices do, the EMI may leak into signal path 150 through connector housing 120. Market pressures are constantly moving toward faster, more reliable data transfer, and EMI leakage is a limiting factor on performance.
A capacitive coupling includes a capacitive material and a conductor coupled to the capacitive material. The conductor and the capacitive material have a form factor to fixedly attach to either a connector housing or a chassis of an electronic device. The form factor of the conductor and the capacitive material is also to removably couple the connector housing and the chassis of the electronic device such that at least one signal frequency is passed between the connector housing and the chassis of the electronic device and a direct current is isolated between the connector housing and the chassis of the electronic device.